Experience Accumulation for Decision Making in Multivariate Time Series

A dynamic stochastic system with multivariate input and multivariate output, possibly controlled in a closed loop, is considered. It is assumed that the input-output relation is describable by a model of a given structure but with a finite set of unknown parameters. The uncertainty of the parameters is characterized by the subjective probability density function. Functional recursion relations are derived describing the evolution of this subjective p.d.f. when it is successively conditioned by the observed data. A self-reproducing form of the conditional p.d.f. is found for the case, when the process is describable by a multivariate regression model and no parameter -- except the order -- is a priori known. This makes it possible to reduce the functional recursion into an algebraic recursion which is easy to perform

The Dynamics of Energy Systems and the Logistic Substitution Model. Vol. 2. Theoretical Part

The application of a certain rule, even if always successful in practice, confronts very strong psychological barriers if it lacks a certain logical frame linking it causally to the body of accepted knowledge. Phenomena rooted in social behavior are always very difficult to "explain" in such a way, because if we rely too much on the basic, irrational, and stochastic roots of our decisions, then the explanation is rejected as "too mechanistic". If on the other hand we rely on the perception people have of themselves, as rational and wise decision makers, then we fall into a maze of ad hoc explanations that strongly resembles local politics. Economists, who have faced a much similar problem, have made a great, partially successful, effort in describing and organizing the monetary measurables of human activity. Although they too miss primary causes they can introduce concepts of minimization and optimization which permit choices and structuring of the systems. Our attempt to "hook" the market penetration rules to the accepted scientific system have followed both routes. Fleck takes the stochastic "irrational" view. Social processes, and introduction of a new technology is a social process, are seen as the envelope of a maze of tiny decisions, causally unrelated, and, like nails in the path of a falling ball, slowing down its chute and "diffusing" its landing point. A good social example of this process is given by the diffusion of an infection e.g. the common flue. Although in a case-by-case analysis the biologist can give a fair causal description of the process, the contacts that lead to the diffusion are within another realm of causality and are better described stochastically. Learning processes are well described in such a way, and they yield logistic curves. Fleck then visualizes the diffusion of a technology as a social learning process under constraints. The stability of the curves is a mark of the stability of man and society as learning structures. The weak point of the theory is that the critical parameters have to be measured post hoc, and they are not reducible to other measurements that could be made before the penetration is initiated. Peterka on the other hand follows a more classical route, taking economics as a driving force. He assumes that an industry to expand has to generate profits. External capital can produce some time-shifts, providing actual money for expected gains, but the picture is not much blurred. Consequently, as substitution is driven by differential growth rates, these rates must be driven by differential profits. Perhaps a weak point of this theory is that differential profits must be constant (if smoothed) over long periods in order to produce well-behaved logistics. This feeds back to regular progress curves and automatic price leveling. We can invert the reasoning and look for the stable progress curves and price leveling whose existence can be postulated from the very regular evolution of market penetration curves. This would greatly add to our understanding of the system. The treatment by Peterka is quite general and produces curves which can specialize as logistic, but may also have more complex expressions. In general, the "graininess" of the data does not permit to distinguish between the various curves, and we usually stick to our logistic, which has the great advantage of straightforward simplicity. Altogether we think that the basic objective of the grant has been fulfilled. We explored the field experimentally showing the great efficiency of our model in organizing data, and we tried two ways to bring its working under logical scrutiny. The fact that during this operation we have presumably generated more problems than we solved is a good indication that we are plowing a fertile field

Macrodynamics of Technological Change: Market Penetration by New Technologies

Progress in technology is viewed as a continuing historical process during which existing forms of satisfaction of human needs are replaced by new and superior ones. A mathematical model is developed describing this process for any number of competing technologies satisfying the same need. The state of competition is characterized by market shares held by particular technologies and the model gives the evolution law for this state. The approach adopted in the derivation of the model is based on long-term balance of capital flows governing production using different technologies. Both deterministic and stochastic versions of the nonlinear dynamic model are presented. Computer subroutines are given for estimation of model parameters from historical data and for forecasting future development of the process. The model is applied to the substitution of primary energy sources in world energy consumption, including the forecast of market penetration by nuclear energy

The Dynamics of Energy Systems and the Logistic Substitution Model. Executive Summary

This is a report on the work done at the International Institute for Applied Systems Analysis in 1976 to 1977 under a grant from Volkswagenwerk Foundation, whose objective was to explore the potential and the mechanisms of logistic analysis to describe the structure and the evolution of energy systems. Volume One contains the phenomenological part. About 300 cases were examined, some of which are reported in detail. The quality of the logistic description is generally excellent, even for cases extending 150 years into the past and with all the perturbations such a long time span entails, and consequently we thought it appropriate to extend the description into the future and use it for prediction. This was not really the objective of the grant but 'it naturally arises from the work and provides food for thought. Projections in the current literature appear to be in fact strongly inconsistent with the past, which casts doubts on their realizability, and are even internally inconsistent, which reinforces these doubts. The fact that numerous "free" choices at the social level lead to very regular overall patterns should perhaps temper the feeling of being caught in a deterministic clockwork. In Volume Two, devoted to the theoretical work, F. Fleck deals specifically with this problem showing the final regularity derived from a set of stochastic, i.e. "free", decisions. V. Peterka, on the other hand, operates at a more aggregated level, where one can start to speak of economic determinism. He describes a form of fate we are more ready to accept, if only grudgingly. Our exploration has generated more problems than we have solved; thus the field appears very fertile for future research

Targeting of the Plzf gene in the rat by transcription activator-like effector nuclease results in caudal regression syndrome in spontaneously hypertensive rats

Recently, it has been found that spontaneous mutation Lx (polydactyly-luxate syndrome) in the rat is determined by deletion of a conserved intronic sequence of the Plzf (Promyelocytic leukemia zinc finger protein) gene. In addition, Plzf is a prominent candidate gene for quantitative trait loci (QTLs) associated with cardiac hypertrophy and fibrosis in the spontaneously hypertensive rat (SHR). In the current study, we tested the effects of Plzf gene targeting in the SHR using TALENs (transcription activator-like effector nucleases). SHR ova were microinjected with constructs pTAL438/439 coding for a sequence-specific endonuclease that binds to target sequence in the first coding exon of the Plzf gene. Out of 43 animals born after microinjection, we detected a single male founder. Sequence analysis revealed a deletion of G that resulted in frame shift mutation starting in codon 31 and causing a premature stop codon at position of amino acid 58. The Plzftm1Ipcv allele is semi-lethal since approximately 95% of newborn homozygous animals died perinatally. All homozygous animals exhibited manifestations of a caudal regression syndrome including tail anomalies and serious size reduction and deformities of long bones, and oligo- or polydactyly on the hindlimbs. The heterozygous animals only exhibited the tail anomalies. Impaired development of the urinary tract was also revealed: one homozygous and one heterozygous rat exhibited a vesico-ureteric reflux with enormous dilatation of ureters and renal pelvis. In the homozygote, this was combined with a hypoplastic kidney. These results provide evidence for the important role of Plzf gene during development of the caudal part of a body-column vertebrae, hindlimbs and urinary system in the rat

Differential postural effects of plantar-flexor muscles fatigue under normal, altered and improved vestibular and neck somatosensory conditions

The aim of the present study was to assess the effects of plantar-flexor muscles fatigue on postural control during quiet standing under normal, altered and improved vestibular and neck somatosensory conditions. To address this objective, young male university students were asked to stand upright as still as possible with their eyes closed in two conditions of No Fatigue and Fatigue of the plantar-flexor muscles. In Experiment 1 (n=15), the postural task was executed in two Neutral head and Head tilted backward postures, recognized to degrade vestibular and neck somatosensory information. In Experiment 2 (n=15), the postural task was executed in two conditions of No tactile and Tactile stimulation of the neck provided by the application of strips of adhesive bandage to the skin over and around the neck. Centre of foot pressure displacements were recorded using a force platform. Results showed that (1) the Fatigue condition yielded increased CoP displacements relative to the No Fatigue condition (Experiment 1 and Experiment 2), (2) this destabilizing effect was more accentuated in the Head tilted backward posture than Neutral head posture (Experiment 1) and (3) this destabilizing effect was less accentuated in the condition of Tactile stimulation than that of No tactile stimulation of the neck (Experiment 2). In the context of the multisensory control of balance, these results suggest an increased reliance on vestibular and neck somatosensory information for controlling posture during quiet standing in condition of altered ankle neuromuscular function

A drifting impact oscillator with periodic impulsive loading: Application to percussive drilling

Peer reviewe

Emission decay and energy transfer in Yb/Tm Y-codoped fibers based on nano-modified glass

We report the results of an experimental investigation and theoretical analysis of luminescence decay in Yb/Tm Y-codoped fibers based on nano-modified glass. Based on the experimental results, numerical simulations allowed us to estimate the energy transfer efficiency between Yb3+ and Tm3+ ions. It was shown that yttria enhances the Yb/Tm energy transfer making fibers with Y-codoping a promising candidate for the development of light sources for laser applications and up-conversion emitters for visualization applications. These fibers demonstrate energy transfer efficiency of ∼50%, which makes them attractive for diode-pumping of Yb-ions at a wavelength of 975 nm